A woman in her ６０s who was diagnosed as having hypercalcemia and hyperparathyroidism was referred to our hospital. Serum calcium and intact parathyroid hormone levels were１１．４mg/ ml and １０７ pg/ml, respectively. Chest computed tomography revealed an enhanced mass measuring approximately１．５cm located in the anterior mediastinum. ９９mTc-Methoxy-isobutylisonitrile scintigraphy demonstrated an anterior mediastinal mass. These findings suggested an ectopic parathyroid tumor located in the mediastinum. The patient underwent resection of the parathyroid tumor with video-assisted thoracic surgery（VATS）. The operation time was １１４ min. The postoperative day１（POD１）calcium level rapidly decreased to８．３mg/ml. The patient was discharged on POD５, and there have been no signs of recurrence １ year after the surgery. Parathyroidectomy by VATS for ectopic mediastinal parathyroid tumors is advantageous because it is less invasive and more cosmetic. VATS may be used as a standard approach for ectopic mediastinal parathyroid tumors. We report the surgical treatment of a case of ectopic mediastinal parathyroid adenoma using video-assisted thoracoscope.